Description of the Related Art
The present invention relates to an imaging device that images a target object mounted on a table.
In order to compensate for insufficiency of light quantity at the time of imaging the target object mounted on the table by using a camera head, the imaging device of this type employs an illumination unit to illuminate the target object on the table. The imaging device also employs arms to respectively hold the camera head and the illumination unit with respect to the table or employs a holding arm for the camera head to also hold the illumination unit. The use of the holding arm(s) is disclosed in, for example, Japanese Patent Laid-open Gazette No. 2004-274503.
However, it was pointed out that the imaging device disclosed in the above-mentioned Patent Document presents the following problems not only in the course of imaging the target object but also in the course of preparing for the imaging or of being stored, or when a user tries to connect the device with an external device or to treat the illumination unit, etc.
In such device, the camera head i.e. a precision instrument is held with respect to the table by means of the arm. Therefore, the camera head is preferably held in an attitude as stable as possible when the device is not in use. For example, the holding arm of the camera head may be inclined toward the table side to bring the camera head closer to the table side and reduce an overall height of the device. In some cases, the holding arm of the illumination unit may also be inclined toward the table side to bring the illumination unit laid over the table top surface. At the time of using the device (or at the time of imaging), a user of the device may return the arms to their respective given positions such that the camera head may be located above the table or the illumination unit may illuminate the target object from the above.
The holding arm for the camera head and the holding arm for the illumination unit are generally rotated in such case, and it was conventionally necessary to rotate these arms independently from each other. In case where a locking mechanism is provided between the holding arm for the camera head and the holding arm for the illumination unit, as disclosed in the above-mentioned Patent Document, it was necessary to enable the locking mechanism before rotating either one of the arms.
In the meantime, it is also necessary to reposition the illumination unit independently according to shape or condition of the target object or depending on absence or presence of glare of illumination in the camera head. However, in order to reposition the illumination unit independently by rotating the holding arm, it is necessary to release the locking mechanism beforehand. Therefore, a user of the device must consider whether the locking mechanism is enabled or released every time rotating the arm, which is disadvantageously complicated.
In case where the rotation of the holding arm offers a high degree of freedom to the excursion of the illumination unit, the glare of illumination in the camera head can be corrected or reduced through the repositioning of the illumination unit. Downsizing of the device, however, may introduce some restrictions on location for installing the illumination unit, length of the holding arm of the illumination unit, or the like, and may cause the repositioning of the illumination unit to be insufficient to reduce or correct the glare of illumination in the camera head. Improvement in usability of the device is thus required.
With the foregoing in view, the present invention is purposed to improve usability of an imaging device that images a target object mounted on a table.